Customised Debugger Output using DebuggerDisplay Attributes

 

Debugger display attribute helps to customized debugger message which in turn create more meaningful debug messages.

When we try debugging the below sample code

 var order = new Order
                {
                    OrderId = Guid.NewGuid(),
                    OrderDate = DateTime.Now,
                    Amount = 100.00M,
                    Customer = new Customer()
                        {
                            Id = Guid.NewGuid(),
                            Name = "Arjit"
                        }
                };
 
 

when debugged the sample code above and hover the order variable we can see the name of the Type the order variable is holding. When implementing the debugger attributes the same code is seen like below in debug mode

Lets see How to implement this For creating custom debug messages we need to decorate class with DebuggerDisplay.

 [DebuggerDisplay("New Order is Created By {Customer.Name} on 
 {OrderDate.ToShortDateString()} For ${Amount}")]
    class Order
    {
        public Guid OrderId { get; set; }
        public DateTime OrderDate { get; set; }
        public decimal Amount { get; set; }
        public Customer Customer { get; set; }
    }
    [DebuggerDisplay("New customer is {Name}")]
    class Customer
    {
        public Guid Id { get; set; }
        public string Name { get; set; }
    }

If You don’t want the properties to be appearing on debug window the use

 
 [DebuggerBrowsable(DebuggerBrowsableState.Never)]
  public Guid Id { get; set; }

Row Constructor - Multiple Row Inserts Using Single SQL Query

Row constructor feature of SQL Server 2008 help with single query to insert multiple rows

Old Approach

 

insert into Customer(id,name,Age) values (100,'Ricardo',45)
insert into Customer(id,name,Age) values (101,'Michael',42)
insert into Customer(id,name,Age) values (102,'Antony',44)
insert into Customer(id,name,Age) values (103,'Zeus',43)

New Approach

 
 
insert into 
 Customer(id,name,Age)
 values
   (100,'Ricardo',45),
   (101,'Michael',42),
   (102,'Antony',46),
   (101,'Zeus',43)

Distinct() LINQ

Distinct() in LINQ is usually used to return Distinct item based on default comparison logic.

  
string[] customer = { "Jeniffer", "Steve", "Anderson", "Evan" };
var distinctCustomerList = from customerList in
                 customer.Distinct()
                 select customerList;

 

We need to tell Distinct to ignore the case by following.

 string[] customer = { "Jeniffer", "Steve", "Anderson", "Evan", "EVAN" };

 var distinctCustomerList = from customerList in
     customer.Distinct(StringComparer.CurrentCultureIgnoreCase)
     select customerList;

This is pretty straight forward and LINQ uses its default Compare logic to find Distinct.
The default Compare Logic need to be changed when working on custom objects like below

 
    public class Customer
    {
        public string CustomerId { get; set; }
        public string FirstName { get; set; }
    }

We need to implement IEquatable interface for determining equality of instances.

  
public class Customer : IEquatable
    {
        public string CustomerId { get; set; }
        public string FirstName { get; set; }

        public bool Equals(Customer other)
        {
            //Check whether the compared object is null. 
            if (Object.ReferenceEquals(other, null)) return false;

            //Check whether the compared object references the same data. 
            if (Object.ReferenceEquals(this, other)) return true;

            //Check whether the Customer' properties are equal. 
            return CustomerId.Equals(other.CustomerId) && FirstName.Equals(other.FirstName);
        }

        public override int GetHashCode()
        {

            // Get the hash code for the Textual field if it is not null.
            int hashTextual = CustomerId == null ? 0 : CustomerId.GetHashCode();

            // Get the hash code for the Digital field.
            int hashDigital = FirstName.GetHashCode();

            // Calculate the hash code for the object.
            return hashDigital ^ hashTextual;
        }
    }

Finally call the Distinct methods to filter out duplicates

  
 var cList = new List();
          cList.Add(new Customer { CustomerId = "100", FirstName = "Jeniffer" });
          cList.Add(new Customer { CustomerId = "100", FirstName = "Steve" });
          cList.Add(new Customer { CustomerId = "102", FirstName = "Anderson" });
          cList.Add(new Customer { CustomerId = "103", FirstName = "Evan" });
          cList.Add(new Customer { CustomerId = "103", FirstName = "Evan" });
          IEnumerable lstCustomer = cList.Distinct();